Pneumatically operated fastener-driving machine

ABSTRACT

1. In a driving machine of the character described including a motor and means for controlling said motor having a control member movable between motor activating and motor inactivating positions: A PIVOTED LEVER TRIGGER; A PLUNGER TYPE SAFETY TRIGGER; A LEVER PIVOTALLY CONNECTED TO SAID LEVER TRIGGER AND OPERATIVELY RELATED TO SAID SAFETY TRIGGER AND TO SAID CONTROL MEMBER TO DRIVE THE CONTROL MEMBER INTO MOTOR ACTIVATING POSITION BY CONCURRENT OPERATION OF THE TRIGGERS; AND REMOVABLE MEANS NORMALLY RESTRAINING SAID LEVER TRIGGER AGAINST OPERATING MOVEMENT OF SAID CONTROL MEMBER EXCEPT WITH CONCURRENT OPERATION OF THE SAFETY TRIGGER, REMOVAL OF SAID REMOVABLE MEANS ENABLING OPERATION OF SAID LEVER BY THE LEVER TRIGGER TO MOVE SAID CONTROL MEMBER THROUGHOUT ITS OPERATIVE RANGE INDEPENDENTLY OF SAID SAFETY TRIGGER.

United States Patent Walter Charles Panock [73] Assignee Spotnails,lnc.

[54] PNEUMATICALLY OPERATED FASTENER- Primary ExaminerGranville Y. Custer, Jr. Attorney-l. Walton Bader CLAIM: 1. In a driving machine of the character described including a motor and means for controlling said motor having a control member movable between motor activating and motor inactivating positions: a pivoted lever trigger; a plunger type safety trigger; a lever pivotally connected to said lever trigger and operatively related to said safety trigger and to said control member to drive the control member into motor activating position by concurrent operation of the triggers: and removable means normally restraining said lever trigger against operating movement of said control member except with concurrent operation of the safety trigger, removal of said removable means enabling operation of said lever by the lever trigger to move said control member throughout its operative range independently of said safety trigger.

PATENTEDUBT 1 2:97: 3.6121379 SHEET 3 OF 3 PNEUMATICALLY OPERATED FAS'I'ENER-DRIVING MACHINE This invention relates to improvements in pneumatically operated fastener-driving machines of the type especially useful for industrial purposes utilizing heavy staples, nails, pins, corrugated fasteners, and the like, and more particularly concerns new and improved combination manual and work-actuated control mechanism for such machines.

In pneumatic machines of the kind to which the present invention applies, driving of the fasteners is effected with such efficiency and acceleration that if the machine, sometimes also referred to as an air gun, is free fired, that is, operated with the driving nose not contiguous to a work piece into which a fastener is to be driven, the fastener as propelled from the machine may become a dangerous missile.

Heretofore it has been proposed to overcome this danger by providing a plurality of valves for controlling the compressed air and means by which one of the valves is operated manually and the other of the valves is operated by the workpiece, and requiring both of the valves to be operated concurrently in order to effect each firing, that is, driving of the fastener driver to drive a successive fastener. While such multiple valve arrangements have been effective as safety devices, they have added substantially to the number of parts required in the machine and thus have added a substantial element of cost. However, a possible more serious objection has been the slowdown in operative response of the machine as compared to a machine having but a single control valve in the pneumatic system.

It is, therefore, an important object of the present invention to provide a new and improved safety means for pneumatic fastener-driving machines which affords all of the advantages of a single control valve for the pneumatic system while retaining the advantages of the correlated manual and work-actuated valve-operating mechanisms of the order of those heretofore employed.

Another object of the invention is to provide a new and improved safety device for pneumatic fastener-driving machines.

A further object of the invention is to provide a novel trigger mechanism for actuating a single pneumatic control valve of a fastener-driving machine, or the like, involving selective and coordinated manual and work-engageable operating members.

Still another object of the invention is to provide a new and improved combination manual and work-actuated trigger mechanism for a pneumatic control valve of a fastener-driving machine or the like embodying only three operating parts.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings, in which:

FIG. I is a fragmentary side elevational view of a pneumatic fastener-driving machine embodying features of the invention, with parts broken away and in section to reveal details of structure;

FIG. 2 is a sectional elevational detail view taken substantially on the line Il-ll of FIG. I;

FIG. 3 is a fragmentary elevational detail view taken in the plane of line III-Ill of FIG. ll;

FIG. 4 is an enlarged fragmentary side elevational view of the machine showing the relative disposition of the safety mechanism parts when the manual trigger element is operatively actuated and before the work-engaging actuator or trigger has been operated;

FIG. 5 is a similar side elevational view showing all of the trigger elements in the positions thereof when the pneumatic control valve is operated to actuate the fastener-driving mechanism in a driving stroke; and

FIG. 6 is a fragmentary sectional detail view taken substantially on the line VI-VI of FIG. 5.

In the illustrated embodiment, a manual pneumatically actuated fastener-driving machine of the type adapted to drive staple, nail or pin types of fasteners includes a housing 10 which may be constructed of one or more castings made of aluminum or other lightweight material. On the lower portion of the housing is a horizontal magazine section llll within which the fasteners in adhered stick form are adapted to be supported and pushed by any suitable advancing or feeding mechanism (not shown) toward a forward end driving nose structure 12 secured thereto under an upwardly projecting driving head 13. On the upper portion of the housing body I0 rearwardly of and attached to the driving head portion 13 is a manipulating handle 14 suitably spaced above the magazine section llll to afford ample manipulating finger clearance below the handle.

Within the driving head section 13 of the casing or housing of the machine is asubstantial volume fluid reservoir space 15 with which an auxiliary reservoir space 17 within the handle 114 communicates freely. Pneumatic pressure fluid such 'as compressed air is adapted to be delivered into the reservoir, such as through the handle reservoir space 17 from any suitable source (not shown) in a manner well known in the art. In machines of this type, compressed air under pressures about p.s.i.g. is customary.

Within the head section 13 is a pneumatic motor including an upright cylinder 18 having its upper end adjacent to the upper end of the head section 13 and from which the reservoir space 15 opens upwardly into a reservoir extension cavity in a generally inverted cup-shaped closure cap 19 detachably secured in any suitably fashion to the top of the head section 13.

Within the cap 19 is provided a vertical cylindrical surface 20 of desirably larger diameter than the cylinder I8 and has vertically reciprocable therein a control poppet valve piston member 21 for controlling entry of compressed air from the reservoir 15 into the cylinder 18. On its lower face the control valve piston 21 carries a sealing ring 22 which engages upon the upper edge seat on the cylinder 18.

Operable within the cylinder I8 is a working or driving piston 23 of generally spool shape which is normally maintained in a ready, upper position due to an area differential acted on by compressed air from the reservoir 15 through an air-retum opening 24 in the wall of the cylinder. Extending downwardly from the lower end of the piston 23 is a fastenerdriving blade 25 which has its lower end operatively aligned with a vertical driveway 27 in the nose assembly 12 and comprising a vertical groove in a nose plate 28 (FIGS. 1 and 6) bearing against a facing plate 29 having a doorway 30 leading from the magazine II and guiding fasteners therefrom into the driveway 27.

In the nonoperating condition of the machine, and during retum-stroke movement of the driving piston 23, the volume above the driving piston is exhausted to atmosphere through means comprising a vertical passage 31 (FIG. I) through the control valve piston and an upwardly projecting guide stem 32 and at such time spaced from a closure valve disk 33 seated at the upper end of a blind end guide bore 34 opening downwardly through the closure cap 119 and having an exhaust port 35 communicating therewith adjacent to the resilient valve seat 33. At this time, the cylinder control valve member 21 is seated in closing relation on the top of the cylinder 18 under the influence of a light biasing; spring 37 and air pressure from the reservoir l5 acting on top of the poppet valve piston in the upper end of the poppet valve cylinder 20.

Opening movements upwardly of the poppet valve 21 drives the upper valve end of the guide stem 32 into sealing engagement with the seat 33 and opens the upper end of the cylinder 18 to the pressure in the reservoir 15 to drive the piston 23 in a fastener-driving stroke. Such unseating of the poppet valve 21 is effected by bleeding off to atmosphere the air pressure over the poppet valve so that the pressure in the reservoir 15, acting on the under side of the margin of the poppet valve, will snap the poppet valve open, Both introduction of pressure air and bleed off are effected through a port 38 opening into the top of the poppet valve cylinder chamber 20 and communicat ing through a generally vertical passage 39 in the head section 113 and the closure cap 19 with a control valve 40 which is desirably located substantially within and at juncture of the handle 14 with the head section.

In a simple and efi'rcient structure, the control valve 40 comprises an elongated tubular barrel body 41 having a head end portion 42 engaged in a complementary downwardly opening socket 43 within a boss 44 provided in the housing at the upper side of the handle-head juncture. Communication is afforded through the head 42 between the reservoir and the passage 39. For this purpose, the valve body 41 has a longitudinal bore 45 extending therethrough, the upper end of which registers with a port 47 opening into the reservoir 15. As shown by the directional arrows in FIG. 1, compressed air entering through the port 47 passes into the valve bore 45 and by way of lateral ports 48 in the head 42 into an annular registration groove 49 in the periphery of the head and thence into the lower end of the passage 39 which opens into the socket 43 in alignment with the groove. Thereby, the poppet valve 21 is normally pressurized.

Nonnally adjacently below the ports 48 a pluglike valve head 50 blocks escape of pressure fluid downwardly through the valve bore 45. When it is desired to unseat the poppet 21 to drive the piston 23 in a fastener-driving stroke, the valve 50 is moved into position above the ports 48 whereby to provide a barrier between the port 47 and the ports 48 and to bleed off pressure from the poppet valve chamber downwardly through the valve bore 45. To this end, the valve 50 has a reduced diameter depending stem 51 having on its lower end an elongated larger diameter but longitudinally flatted guiding and actuating portion 52 normally biased downwardly by means of a coil compression spring 53 thrusting against its upper end and against a downwardly facing shoulder 54 spaced upwardly from the shoulder provided by the guide portion 52.

Normally, the biasing spring 53 and compressed air thrusting against the crown of the valve 50 urge the valve downwardly so that the guiding and actuating portion or plunger 52 projects downwardly substantially beyond the lower end of the valve body 41 which is in its lower end portion engaged in a bore 55 aligned with the socket 43 and opening downwardly, a retaining pin 57 securing the valve body in place.

Downward projection of the bleeder valve plunger 52 is limited by engagement with a valve-actuating mechanism including a manually operable trigger lever 58 operatively mounted under the control valve in a convenient position below the front end of the handle 14 for actuation by the index finger of a hand grasping the handle,

In a desirable construction, the digitally operable trigger 58 is of a generally U-shaped cross section afl'ording a lower transverse downwardly facing finger-engageable web flange portion 59 providing a lever body which is herein elongated in a front-to-rear direction. Opposite integral side flanges 60 extend upwardly from the lever body 59 and terminate at their rear ends with the rear edge of the body. Forwardly the side flanges 60 project a substantial distance beyond the front edge of the lever body 59 and provide means whereby the trigger lever is pivoted to the housing, being desirably provided with upwardly extending similar parallel, transversely aligned journal ears 61 which freely receive therebetween a mounting ear 62 integral with the housing 10 and more particularly the head section 13 adjacent juncture of and below the handle 14 and fonvardly adjacent the bore 55. Means providing a pivotal connection of the lever ears 61 to the mounting ear 62 comprise a pin 63. Since the trigger lever 58 serves as stop means delimiting downward, outward protracted displacement of the bleeder valve under the influence of the biasing spring 53 and air pressure, stop means are provided on the trigger lever to maintain it in an at-rest, downward limit of movement in a generally horizontal position, and herein comprising respective stop lugs 64 on the front extremities of the trigger side flanges 60 and projecting toward one another under the mounting ear 62 serving as a stop shoulder against which the lugs thrust. Through this arrangement, upward swinging of the trigger lever 58 from its normally valveplunger-biased horizontal position drives the valve plunger 52 and the bleeder valve upwardly toward bleedoff position.

According to the present invention, means are provided for optionally restraining the trigger lever 58 from fully retracting the bleeder valve to bleedoff position until the driving nose 12 of the machine has been placed in such contiguity to a fastener-receiving surface S, such as represented in FIGS. 4 and 5, as to receive the driven fastener when the pneumatic motor is drivingly actuated. To this end, means are provided for stopping upward swinging bleeder-valve-retracting movement of the trigger lever 58, conveniently comprising generally upwardly extending respective stop lugs on the journal ears 61 and provided with generally forwardly facing respective stop shoulder edges 67 engageable with properly relatively forwardly located stop shoulder means on the upper portion of the mounting ear 62 and herein comprising a selectively removable pin 68. Thereby, in the absence of the stop pin 68 free digital operation of the bleeder valve 50 by means of the manual trigger 58 is enabled, With the an pin 68 in position, the manual trigger lever 58 will move the bleeder valve into only partially retracted position, being brought to a stop desirably as close as practicable short of uncovering the valve ports 48 to the bleedoff passage in the valve body 41.

New and improved means for actuating the bleeder valve through the final increment of bleedoff movement comprise a secondary or trip trigger 69. lna practical, efficient construction, the trip trigger 69 comprises an elongated lever mounted for two-step actuation, being for this purpose pivotally attached as by means of a pin 70 to and between the primary trigger flanges 60 at a suitable position rearwardly from the valve plunger 52 and projecting forwardly into underlying continual engagement with the tip of the plunger. Normally, the trip trigger 69 rests against the upper face of the trigger body 59. Hence, the trip trigger is adapted to act, in effect, as a part of the primary trigger 58 where the primary trigger is free, by omission of the stop pin 68, to effect full bleedoff for firing operation of the bleeder valve 50. Also, in the safety stop operation of the primary trigger 58, the trip trigger 69 functions as a part of the primary trigger in the close-ready actuation of the bleeder valve to its position just short of uncovering the bleeder valve ports 48, as defined by the stop shoulders 67 and the stop pin 68 (FIG. 4).

For actuation of the trip trigger 69 in a second-step bleedervalve-opening movement, after the first-step movement with the primary trigger 58, a tripping extension 71 from the trip trigger lever projects into tripping accessibility beyond the front edge of the trigger lever body 59, and desirably downwardly and forwardly as shown. Short second-class leverage movement of the trip lever 69 upwardly about its pivot 70 then effects bleedoff movement of the bleeder valve 50 since after the full first-step actuation of the trip trigger only the slight further movement of the bleeder valve 50 to uncover the bleeder ports 48 rapidly causes actuation of the pneumatic motor.

Safety trigger means adapted for actuation by the workpiece or surface into which a fastener is to be driven are provided to operate the trip trigger 69 concurrently either in second-step sequence with respect to the first-step actuation of the trip trigger by the manual trigger 58, or simultaneously, or in first-step relation with the manual trigger functioning in second-step sequence. For this purpose, a vertically elongated, plunger-type work-engageable trigger finger 72 is provided which is substantially narrower than the width of the nose structure 12 and is mounted for reciprocal slidable actuation longitudinally on the front face of the nose plate 28 by means comprising a complementary guide bracket 73 which is desirably attached removably to the front plate by means of screws 74. Minimum practical gauge or thickness of material is adapted to be used in the trigger finger 72 by providing it with a longitudinal reinforcing rib 75 (FIG. 6) which, at the work-engaging tip of the finger, affords, in effect, an increased-thrust-bearing surface to enhance work surface engagement and to minimize impingement damage where the same is advanced to the work surface with undue vigor.

Normally, the finger trigger 72 projects a predetermined distance below the tip of the driving guide nose 12, as shown in FIGS. 1 and 4. This normal projection of the finger is defined by a downwardly facing shoulder provided by a lateral arm 77 integral with the upper end of the finger and engaging the top of the guide bracket 73 affording an upwardly facing stop. Normally, the trigger finger 72 is biased into its lowermost position by means such as a compression spring 73 thrusting downwardly between the overhanging housing and the lateral arm 77.

Operative connection of the safety trigger finger 72 with the trip trigger extension 71 is effected through the arm 77 and an integral rearward extension 79 thereon which extends in clearance relation alongside the front portion of the magazine l1 and supports rigidly on its rear portion an upwardly extending trip arm 80 having on its upper end portion upwardly facing shoulder means 811 opposing the underside of the trip trigger extension 71. Normally, a lost-motion relationship is afforded by a spacing of the shoulder 81 below the trip extension 71, in practice about one-eighth inch.

For substantial-size tolerance allowances and to maintain registration of the trip arm 80 and the trip trigger extension 711, an alignment finger 82 extends integrally upwardly from the center of the shoulder 8ll into a longitudinally elongated clearance slot 83 in the trigger extension 71.

A guide against rearward tilting of the trip arm 80 is afforded by a guide bracket including a transverse horizontal guide bar M positioned for slidable engagement by the back of the arm 80 and having upwardly extending respective mounting arms 85 on its ends disposed in spaced parallel relation and supported by the pivot pin 63 and the stop pin 68.

In operation, assuming that the manual trigger 58 has been depressed, that is, swung upwardly to its close-ready bleedervalve-actuation position defined by the stop shoulders 67 and the stop pin 68, as shown in FIG. 4, and with the safety trigger 72 fully extended, the trip trigger is tilted down so that its extension 71 comes to rest on the shoulder 81. Then, within a very short range of initial upward movement of the safety trigger 72, shifting of the trip trigger 69 to move the control valve 50 above the control parts 48 effects operation of the pneumatic motor to drive a fastener. This occurs while the driving nose 112 of the machine is still in motion with the machine toward the work surface S, which is a distinct ad vantage in driving long industrial fasteners because the mo mentum of the machine mass is added to the driving force of the driving blade. Recoil is thus reduced. Such recoil as does occur as a consequence of driving long fasteners is amply accommodated within the free reciprocal range of the trigger finger 72 between the initial increment of bleeder-valve-opening motion and the remaining distance in the retractional range of the trigger finger. Because of the advantageous valveactuating leverage relationship afforded by this trigger system, substantially increased speed of driving operation is afforded for experienced operators.

Because the manual trigger when fully depressed, positions the bleeder valve 50 in such close-ready relation to the bleeder ports 48, extremely efficient, rapid so-called bump firing is enabled. In this, the operator maintains the trigger 58 continuously depressed and drives successive fasteners by moving the safety plunger or work trigger 72 against successive spots to receive fasteners.

For so-called stitch firing, the driving nose 12 of the machine is held in position against and moved over the work surface without raising it while successive fasteners are driven, and this is substantially facilitated by the advantageous trigger system herein. As visualized in dash outline in FIG. ll, when the work trigger 72 is fully retracted while the manual trigger 58 is fully relaxed, the trip arm 80 through its pivotal connection with the trip trigger lever holds the trip trigger 69 upwardly, in substantially the same leverage relationship to the bleeder valve plunger 52 as when the trip trigger is raised by the manual trigger with the work trigger plunger extended in accordance with the showing in FIG. 4. That is, the bleeder valve 50 is raised into the close-ready position relative to the bleeder ports d8. Hence, only a small increment of leverage motion of the manual trigger 58 will cause actuation of the pneumatic motor. An experienced operator can thus stitchfire at a highly advantageous rate.

Even though the close-ready preparation of the bleeder valve 50 by actuation of either of the manual or safety triggers affords quite advantageous firing sensitivity, undiminished safety factor is maintained because the intermediate or secondary or trip trigger requires concurrent operation of the primary safety and manual triggers. When it is desired to dispense with the safety trigger 72, it can be readily dismantled or may be omitted and the manual trigger 58 permitted to actuate the bleeder valve throughout its operative range.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a driving machine of the character described including a motor and means for controlling said motor having a control member movable between motor-activating and motoninactivating positions:

a pivoted lever trigger;

a plungebtype safety trigger;

a lever pivotally connected to said lever trigger and opera tively related to said safety trigger and to said control member to drive the control member into motor-activating position by concurrent operation of the triggers; and

removable means normally restraining said lever trigger against operating movement of said control member except with concurrent operation of the safety trigger, removal of said removable means enabling operation of said lever by the lever trigger to move said control member throughout its operative range independently of said safety trigger.

2. In combination in a fastener-driving machine including a housing having a front head section supporting a fastener driver having a driving motor and a nose structure mounted at the front of a magazine attached to the lower end of the head structure to deliver successive fasteners into the nose structure to be driven therefrom by the driver into a work surface toward which the nose structure is directed:

a handle attached to the head structure in spaced relation above the magazine;

means for controlling operation of the motor including a plunger which is mounted to project normally downwardly below the handle adjacent to said head section;

a manually operable trigger of generally U-shaped cross section having an upwardly facing body and integral opposite upwardly extending spaced side flanges projecting forwardly beyond the forward end of said body:

an integral trigger-supporting car on said head section adjacent and below juncture of said handle and the forwardly projecting portions of the trigger side flanges receiving said ear therebetween;

a pivot pin connecting said flange portions to said ear;

stops on said flange portions engaging under said ear and thereby defining lower limit of pivotal movement of the manual trigger;

stop shoulders on said flange portions;

a removable stop pin extending through said ear and engageable by said stop shoulders to limit upward pivotal movement of the manual trigger;

a safety plunger reciprocably mounted on said nose structure and normally projecting therebelow for engagement with a work surface in advance of the nose structure on movement of the nose structure into position for driving a fastener into said surface;

an upwardly projecting trip arm rigid with and movable reciprocably with the safety plunger and having its upper end portion forwardly spaced from but adjacent to said manual trigger body;

a bracket reciprocably guiding said trip arm and mounted on said pivot pin and said stop pin; and

tion of said trip arm, whereby actuation of said trip trigger lever by concurrent operation of said manual trigger and said safety plunger causes the control plunger to be moved fully upwardly for motor activation after removal of said stop pin. 

1. In a driving machine of the character described including a motor and means for controlling said motor having a control member movable between motor-activating and motor-inactivating positions: a pivoted lever trigger; a plunger-type safety trigger; a lever pivotally connected to said lever trigger and operatively related to said safety trigger and to said control member to drive the control member into motor-activating position by concurrent operation of the triggErs; and removable means normally restraining said lever trigger against operating movement of said control member except with concurrent operation of the safety trigger, removal of said removable means enabling operation of said lever by the lever trigger to move said control member throughout its operative range independently of said safety trigger.
 2. In combination in a fastener-driving machine including a housing having a front head section supporting a fastener driver having a driving motor and a nose structure mounted at the front of a magazine attached to the lower end of the head structure to deliver successive fasteners into the nose structure to be driven therefrom by the driver into a work surface toward which the nose structure is directed: a handle attached to the head structure in spaced relation above the magazine; means for controlling operation of the motor including a plunger which is mounted to project normally downwardly below the handle adjacent to said head section; a manually operable trigger of generally U-shaped cross section having an upwardly facing body and integral opposite upwardly extending spaced side flanges projecting forwardly beyond the forward end of said body: an integral trigger-supporting ear on said head section adjacent and below juncture of said handle and the forwardly projecting portions of the trigger side flanges receiving said ear therebetween; a pivot pin connecting said flange portions to said ear; stops on said flange portions engaging under said ear and thereby defining lower limit of pivotal movement of the manual trigger; stop shoulders on said flange portions; a removable stop pin extending through said ear and engageable by said stop shoulders to limit upward pivotal movement of the manual trigger; a safety plunger reciprocably mounted on said nose structure and normally projecting therebelow for engagement with a work surface in advance of the nose structure on movement of the nose structure into position for driving a fastener into said surface; an upwardly projecting trip arm rigid with and movable reciprocably with the safety plunger and having its upper end portion forwardly spaced from but adjacent to said manual trigger body; a bracket reciprocably guiding said trip arm and mounted on said pivot pin and said stop pin; and a trip trigger lever between said flanges above said body intermediately opposing the lower end of said control plunger and having a rear end portion pivotally connected between said flanges with a forwardly extending portion projecting beyond said front end of said body and in pivotal-shouldering opposition to said upper end portion of said trip arm, whereby actuation of said trip trigger lever by concurrent operation of said manual trigger and said safety plunger causes the control plunger to be moved fully upwardly for motor activation after removal of said stop pin. 